In DE GM 84 10 839 and 84 36 564, controllable temperature rolls are described in which the rolls can be heated or cooled with a thermal transfer medium, i.e. a heating or cooling fluid, which can pass through bores close to the cylindrical surface of the roll.
These bores, which extend axially through the roll body communicate with axial bores in the shaft stubs on which the roller is journalled for rotation about the roll axis.
Rolls of this type are widely used in calenders of all types.
The bores in the roll body generally communicate with chambers or hollow spaces formed in the flanges and supplying or distributing the thermal medium. With direct connection of these flanges to the roll body, which has been found to be necessary in earlier systems to provide the openings of the heating bores which communicate with the disk-shaped chambers relatively deeply below the rolling surface since the diameter of the chambers has, in the past, been required to lie inwardly of the circle of screws or bolts by means of which the flanges are affixed to the ends of the roll body.
With the heat transfer bores lying relatively deeply below or inwardly of the surface of the roll, the thermal inertia of the roll is significant, i.e. it is impossible to rapidly vary the roll temperature as may be required under many conditions. Furthermore, it is difficult to minimize the temperature gradient within the roll body where the heat transfer bores are spaced substantially from the peripheral roll surface.
Of course, it is possible to incline the bores in the roll body to allow the bolts or screws to be cleared by the flow passages which can thus run closer to the peripheral surface of the roll, but roll constructions of this type have been found to be inordinately costly and time consuming to fabricate.